Size - 10pcs bits(slotted: 4mm/5mm/6mm; torx: T15/T20; phillips: PH1/PH2, pozi: PZ1/PZ2; square: 1/4') are small enough to operate in tight places/narrow spaces/narrow areas. Bit Length: 25mm/1', Total Length: 77.8mm/3' Material - Those screwdriver bits are made of S2 alloy steel material with a sandblasting finish, high hardness and durability, suitable for industrial use. Features - The drill bit set can be matched with an interface 1/4' torque wrench, ratchet wrench, slide bar, power wrench, and drive square head. Applications - 1/4-inch hexagonal bits feature a positioning nut, adjusting screw rod, and lock nut, a good helper for DIY hand-making and household maintenance. Notice - Do not turn the screws with mismatched size to avoid damage to both the screw and the drill.